{"id":"AZL-83648","summary":"CVE-2026-31593 affecting package kernel for versions less than 6.6.134.1-2","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: SEV: Reject attempts to sync VMSA of an already-launched/encrypted vCPU\n\nReject synchronizing vCPU state to its associated VMSA if the vCPU has\nalready been launched, i.e. if the VMSA has already been encrypted.  On a\nhost with SNP enabled, accessing guest-private memory generates an RMP #PF\nand panics the host.\n\n  BUG: unable to handle page fault for address: ff1276cbfdf36000\n  #PF: supervisor write access in kernel mode\n  #PF: error_code(0x80000003) - RMP violation\n  PGD 5a31801067 P4D 5a31802067 PUD 40ccfb5063 PMD 40e5954063 PTE 80000040fdf36163\n  SEV-SNP: PFN 0x40fdf36, RMP entry: [0x6010fffffffff001 - 0x000000000000001f]\n  Oops: Oops: 0003 [#1] SMP NOPTI\n  CPU: 33 UID: 0 PID: 996180 Comm: qemu-system-x86 Tainted: G           OE\n  Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE\n  Hardware name: Dell Inc. PowerEdge R7625/0H1TJT, BIOS 1.5.8 07/21/2023\n  RIP: 0010:sev_es_sync_vmsa+0x54/0x4c0 [kvm_amd]\n  Call Trace:\n   \u003cTASK\u003e\n   snp_launch_update_vmsa+0x19d/0x290 [kvm_amd]\n   snp_launch_finish+0xb6/0x380 [kvm_amd]\n   sev_mem_enc_ioctl+0x14e/0x720 [kvm_amd]\n   kvm_arch_vm_ioctl+0x837/0xcf0 [kvm]\n   kvm_vm_ioctl+0x3fd/0xcc0 [kvm]\n   __x64_sys_ioctl+0xa3/0x100\n   x64_sys_call+0xfe0/0x2350\n   do_syscall_64+0x81/0x10f0\n   entry_SYSCALL_64_after_hwframe+0x76/0x7e\n  RIP: 0033:0x7ffff673287d\n   \u003c/TASK\u003e\n\nNote, the KVM flaw has been present since commit ad73109ae7ec (\"KVM: SVM:\nProvide support to launch and run an SEV-ES guest\"), but has only been\nactively dangerous for the host since SNP support was added.  With SEV-ES,\nKVM would \"just\" clobber guest state, which is totally fine from a host\nkernel perspective since userspace can clobber guest state any time before\nsev_launch_update_vmsa().","modified":"2026-08-28T17:47:57.121164472Z","published":"2026-04-24T15:16:36Z","upstream":["CVE-2026-31593"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-31593"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.6.134.1-2"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-83648.json"}}],"schema_version":"1.9.0"}